The invention generally relates to circuit board interconnections, and in particular, to an optical interconnect for connecting mezzanine circuit boards to a base or main circuit board.
High-density electronic systems, such as telecommunications systems and computers, generally use a physical design for circuit boards that permits a base board to have connectors that permit the attachment of a supplemental board to add features. For example, PCI is a standard that permits the addition of PCI mezzanine cards to a base board. A standard connector and bus are used to interconnect the functions on the PCI mezzanine card with the base board. This arrangement is particularly useful for adding I/O interfaces, such as network interfaces. Advantageously, boards are customized and new features added without a redesign of the base board.
One problem with the base board/supplemental board arrangement is that the connector and standard bus interface lack the bandwidth, performance and reliability needed to support some advanced services. This severely limits the use of the supplemental boards.
Therefore, a need exists for an additional interface to enhance the uses of a base board/supplemental board arrangement.
In summary, an apparatus is provided with a supplemental high-speed optical interface. The apparatus includes a first circuit board that is spaced adjacent a second circuit board. A light source that transmits an optical signal is coupled to the first circuit board. A photo detector is coupled to the second circuit board. The photo detector is adapted to receive an optical signal from the light source. More specifically, the first circuit board is arranged with respect to the second circuit board such that the photo detector receives the optical signal over an optical transport medium. Preferably, the light source is a laser and the photo detector is a photo diode. The optical transport medium is alternatively, free space or a light pipe. Preferably, another light source is also coupled to the second circuit board and a complementary photo detector is coupled to the first circuit board for two-way communications. A method is provided for operably arranging the circuit boards for communication.